Disk drives comprise a disk and a head connected to a distal end of an actuator arm which is rotated about a pivot by a voice coil motor (VCM) to position the head radially over the disk. The disk comprises a plurality of radially spaced, concentric tracks for recording user data sectors and servo sectors. The servo sectors comprise head positioning information (e.g., a track address) which is read by the head and processed by a servo control system to control the actuator arm as it seeks from track to track.
FIGS. 1 and 2 depict air-bearing surface (“ABS”) and top views, respectively, of a portion of a conventional perpendicular magnetic recording (“PMR”) transducer 10. The conventional transducer 10 includes an intermediate layer 12. The intermediate layer 12 is the layer on which the pole is formed. The intermediate layer 12 may be a leading edge shield or a nonmagnetic layer. A gap layer 20 that may separate the pole 30 from the underlying intermediate layer 12 is shown. The conventional pole 30 and side shield 40 are also shown. For clarity, seed layer(s) are not separately depicted.
The side shields 40 are conformal to the pole 30. Thus, the thickness of the gap layer 20, t, does not vary in the down track direction. Similarly, the thickness of the gap layer 20 does not vary in a direction perpendicular to the ABS until the side shields 40 terminate at the throat height. Stated differently, the walls of the side shields 40 closest to the sidewalls of the pole 30 are substantially the same distance and have substantially the same profile as the pole 30.
Although the conventional transducer 10 may be used to write to media, there may be drawbacks at higher recording densities. At higher recording densities, the components 12, 20, 30 and 40 of the conventional transducer 10 are scaled to smaller sizes. As a result, the write field of the conventional pole 30 may be significantly reduced. In addition, the reverse overwrite loss may be increased. These developments are undesirable. Although these issues may be partially addressed by removal of the side shields 40, this is also undesirable. The side shields 40 are desired to prevent adjacent track interference and to mitigate wide track erasure that may be associated with a smaller side shield throat height.